Electric switch



Aug. 16, 1949.

Filed July 24, 1946 J. A. FAVRE ELECTRIC SWITCH ITM/ent OT His AttornJohn* A. Favre,

1 bym Aug. 16, 1949.

J. A. FAVRE ELECTRIC SWITCH Filed July 24, 1946 2 SheeCS-Shee(l 2Inventor: John A. Peu/Pe His Attowney.

Patented Aug. 16, 1949 ELECTRIC SWITCH John A. Favre. Drexel Hill, Pa.,assigner to General Electric Company, a corporation of New YorkApplication July 24, 1946, Serial No. 685,929

7 Claims. 1

My invention relates to improvements in electric switches and moreparticularly circuit breakers and especially automatic trip-free aircircuit breakers, the opening or which must be sensitively responsive topredetermined circuit conditions.

In an automatic trip-free circuit breaker wherein a thermally responsivetripping element is used to maintain the circuit breaker mechanism inthe closed circuit position, there arises a conict between therequirements of a strong opening force and a sensitive tripping actionfor releasing the circuit breaker mechanism in response to deflection ofthe thermal element. A

strong opening force is desirable for rapid sepa-4 ration of thecontacts. The more of this opening force the thermally responsivetripping element has to overcome, the larger the element has to be andthe greater the space required. Also, the sensitivity and consistency ofresponse is weakened especially for currents in the nature of overloadsfor which a relatively long time delay is desired.

An object of my invention is to provide, for maintaining a circuitbreaker mechanism in the closed circuit position against a relativelystrong opening force, a holding mechanism which has a relativelysensitive release for effecting the opening of the circuit breaker.Another object of my invention is to provide an improved circuit breakermechanism which, although held in the closed circuit position byelectro-responsive tripping means, is readily releasable thereby inresponse to abnormal circuit conditions whether of overload or shortcircuit magnitude. A further object of my invention is to provide animproved automatic trip-free circuit breaker mechanism which, althoughmaintained in the closed circuit position by a thermally responsivetripping element against a relatively strong opening force, issensitively releasable by the action of the thermally responsivetripping element in case of abnormal currents through the circuitbreaker. These and other objects of my invention will appear in moredetail hereinafter.

In accordance with my invention, I provide an electric switch comprisinga movable circuit controlling member and means for moving the member toand maintaining it in the closed circuit position against a relativelystrong opening force. This holding means includes a pivotally mountedlatching lever, a wedgy catch for the lever biased into self-releasingengagement therewith,

and a trip device having a sensitive latch for holding the catch inself-releasing wedging en- (Cl. 20G-116) sagement with the lever. Alsoin accordance with my invention, I provide biasing means tending to movethe catch and trip latch into holding engagement with the latching leverand catch, respectively. For biasing the circuit controlling member tothe open circuit position, I provide an overcenter spring operatingmechanism having an operating element movable in one direction to effectengagement of the latching lever and the catch and in the oppositedirection to eiect engagement of the trip latch and the catch and thento move the circuit controlling member to the closed circuit position.Also in accordance with my invention, the movement of the trip latch tothe holding position is limited by a movable stop which is actuable inresponse to abnormal conditions of the circuit controlled by the circuitbreaker for effecting a release of the latch to cause the opening of thecircuit breaker.

My invention will be better understood from the following descriptionwhen considered in connection with the accompanying sheet of drawings,and its scope will be pointed out in the appended claims.

In the accompanying sheet of drawings, Fig. 1 is a side elevation of onepole of a circuit breaker embodying my invention showing the circuitbreaker in the closed circuit position; Fig. 2 is a front elevation ofthe embodiment of my invention shown in Fig. 1; Fig. 3 is a sectionalelevation similar to Fig. 1 with certain parts broken away forclearness; Fig. 4 is an elevation Similar to Fig. 3 showing the circuitbreaker reset and ready for closing; and Fig. 5 is an elevation similarto Fig. 3 showing the circuit breaker in the tripped open position.

In the several gures of the accompanying drawing, I have illustrated acircuit breaker provided with an operating mechanism embodying myinvention. In these gures only one pole of the circuit breaker is shown,but it will be understood by those skilled in the art that the circuitbreaker may have any desired number of poles and that in case of an oddnumber of poles the operating mechanism will be associated with themiddle pole and in case of an even number of poles the operatingmechanism will be positioned intermediate the two central poles. Asshown. the circuit breaker comprises a base I of suitable insulatingmaterial for supporting'the various parts which may be protected fromdust and falling objects by a cover 2 preferably of suitable insulatingmaterial. Also, suitable insulating barriers, not shown, may beinterposed between adjacent poles of the multipole breaker as is wellknown to the art.

As shown, the circuit breaker comprises one or more circuit controllingmembers 3, one for each pole of the circuit breaker. 'Each circuitcontrolling member 3 is mounted for movement into engagement with acooperating relativeLv sta-v tionary contact 4. In the illustratedarrangement, the circuit controlling member 3 is mounted on a pin 5supported in extensions 5 of the ilanges 1 of a channel-shaped support8. This movable contact support 8 is mounted on a shaft 9 and insulatedtherefrom by an insulating block IIB of square cross section projectingthrough registering openings in the anges I of the support. A lockingand Clamping member II embracing the block I and projecting throughapertures in the web of the support 8 serves to secure the assembly. Inorder to prevent rotation of the movable contact 3 relatively to itssupport 8, the lower end of the contact is slotted for lockingengagement with the web of the support. A flexible connection I2 extendsbetween the movable contact 3 and a terminal I3. In conductiveconnection with this terminal through a terminal block I4 is theU-shaped current conducting and heating element I5 of a thermallyresponsive device such as disclosed in the patent of Albert R. van C.Warrington, No. 2,412,483, filed July 22, 1943, and assigned to theassignee of this invention. Above the heating element I5 is anequalizing element I6 which is electrically insulated from the terminalblock Il and is heat insulated from the outer end of the element I5 soas to prevent direct heat conduction therefrom. The lower leg of themember I5 is connected to a main circuit breaker terminal i1. While Ihave shown and briefly described a thermally responsive element which isparticularly suited for tripping circuit breakers, it is to -beunderstood that my invention is not limited in its application to anypara ticular tripping element.

The relatively stationary contact I is resiliently suspended from anupper terminal block I8 by a leaf spring I9 and connected to theterminal block by a flexible conductor looped around the web 2| of aU-shaped magnetic member. the flanges 22 of which are perforated andsecured to the side members 23 of an arc chute, all as disclosed in thecopending application of Robert M. Bennett, Serial No. 606,374, filedJuly 21, 1945, now Patent No. 2,460,118, dated January 25, 1949, andassigned to the assignee of this invention. The terminal block I8 isconnected to the circuit breaker terminal 24.

For moving the circuit controlling member 3 to and maintaining it in theclosed circuit pition, I provide an overcenter spring operatingmechanism having a latchlng lever 25 which is supported on a pivot pin2B. As shown, the pin 2-5 is mounted in a generally U-shaped frame 21secured to the base I. The latching lever 25 is interconnected with thecircuit controlling member 3 by a toggle comprising links 28 and 29. Thetoggle link 28 is pivotally connected to the latching lever 25 at 33,and the link 23 is pivotallv connected to the circuit controlling member3 at the pin 5. The two links 28 and 28 are pivotallv1 interconnected at3|. For holding purposes in both the circuit closed and open positions,the link 28 is provided with a projection such as an arm 32, shown moreclearly in Figs. 4 and 5, which comes to rest against the inner edge ofthe latching lever 25 near the pivot pin 28 when the circuit breakermechanism is tripped -to the circuit open position, as shown in Fig. 5,and also when the circuit breaker is closed, as shown in Figs, l and 2,to maintain the toggle 28-29 in an overset position whereby to hold thecircuit controlling 5 member 3 in the closed circuit position as long asthe latching lever 25 is held in the latched .position. The pivot pin 23is provided with a compound spacer against which the circuit controllingmember 3 comes to rest in the circuit open position, as shown in Figs. 4and 5, and against which it remains until the circuit breaker is closed.

For self-releasing wedging engagement with the latching lever 25 in thelatched position, I

15 provide, in accordance with my invention, a

of a U-shaped member pivotally supported on the frame 2l at 34. Forobtaining the desired self-releasing wedging engagement, the latchinglever is provided with a relieved shouldered portion which abuts againstthe rear side of the web portion' of the catch 33 at an angle such as totend to move the catch 33 clockwise about its pivot 3d when the latchinglever is in the latched position shown in Figs. 1, 3 and 4. For limitingthe counterclockwise movement of the latching lever 25 during thecircuit opening operation so that it may not ride off the web of thecatch 33, the lever is provided with a second shouldered portion 36. Forbiasing the catch 33 into engagement with the shouldered portion 35 ofthe latching lever 25 when the lever is moved clockwise to the latchingposition, I provide means tending to move the catch 33 into engagementwith the latching lever 25. As shown, this means comprises a hair springtype of torsion spring 3l which is carried on the pin 3e and which isprovided with an arm 38 bearing against the latching lever and an arm 38bearing against a pin 39 mounted between the legs of the catch 33.

Further in accordance with my invention, I provide a trip latch 30 forholding the catch 33 in self-releasing engagement with the trip lever 25to maintain the circuit controlling member 3 in the closed circuitposition after it has been moved to such position. As shown, the triplatch 4I) is mounted on a support ll pivoted in the frame 2l at 32. Inthe tripped open position of the circuit breaker, the trip latch lill isin the rear of the web portion oi the catch 33 under the bias ofsuitable means such as a relatively light spring Q3 which tends to movethe trip latch support ll clockwise into the latching position shown inFigs. 1, 3 and 4. The spring 133 is connected between the pin 39 on thecatch 33 and the support 4I. It will be noted that the pivotal axes ofthe latching lever 25, the catch 33 and the trip latch 43 aresubstantially parallel and that the respective pivotal axis of thelatching lever 25 and the trip latch 40 are substantially in line withthe points of engagement of the latch by the catch and the lever by thelatch to provide a sensitive release oi the lever upon rotary movementof the trip latch out of the line. For limiting the clockwise movementof the trip latch support 4I produced by the spring I3 so 'as tomaintain its under the web portion of the catch 33, the outer end of thesupport 4I is 7o arranged to abut a projection lill carried by thethermally responsive means heretofore described so that the circuitbreaker mechanism may be tripped in response to predetermined currentconditions of the circuit through the circuit breaker. A projection 3l'on the frame 2l prevents overtravel in the clockwise direction oi thetrip latch 40. However, when current above a predetermined amount passesthrough the heated portion l oi' the thermally responsive means, theresultant enect oi this portion and the equalizer portion I6 is to movethe projection 44 upward whereby to eiiect counterclockwise movement ofthe trip latch support 4l so as to release the catch 33 and eiiect theopening of the circuit breaker.

For resetting the latching lever 25 and moving the circuit controllingmember 3 to the closed circuit position, I provide an operating element45 which is movable in one direction, clockwise as viewed in thedrawing, to eil'ect engagement of the latching lever 25 and the catch33. Further in accordance with my invention, I provide a resilientovercenter connection between the operating element 45 and the toggle23-23 which is operative during the reverse or counterclockwise movementof the operating element 45 to effect engagement of the tripping latch40 and the catch 33 and to move the toggle 23-23 overcenter and thecircuit controlling member 3 to the closed circuit position. As shown,the operating element 45 is pivoted in the trame 21 at 45 and isinterconnected to the toggle pin 3| by one or more relatively strongsprings 41 which extend between the toggle pin 3| and projections 48 onthe operating member. In the closed circuit position of the circuitcontrolling member 3, the operating member 45, which as shown consistsof two parallel portions interconnected by an insulated bridging pin 49,comes to rest against parallel projecting arms 50 on the frame 21 withthe springs '41 under relatively high tension to insure a quick openingVof the circuit breaker. In the circuit open position, the insulated pin43 on the operating element 45 comes to rest against the outer upperedge 5I oi' the latching lever 25 adjacent the pin 30, as shown in Fig.5, with the springs 41 under a materially relieved tension.

For easy manipulation of the operating element 45, I provide a manuallyoperable member 52 which is siidably positioned within the cover 2between guides 53 and 54 and provided with a handle projection 55 whichrides between the sides of a slot 56 in the cover. The member 52 isprovided with notched portions 51 which engage the pins 48 on theoperating element 45. It will be observed that the position of theoperating member 52 is indicative of the circuit breaker position. Thus,for example, in the closed position of the circuit breaker shown inFigs. 1 and 3, the projection 55 is at its highest point in the slot 55;and in the reset' or manually opened position of the circuit breakermechanism, the projection 55 is at its lowest point in the slot 56;while in the tripped open or automatic trip indicating position of thecircuit breaker mechanism, the projection 55 is at an intermediate pointin the sloi'l 55.

Assuming the parts in the closed circuit position as shown in Figs. 1, 2and 3, then in the event of current ilow through the circuit breaker ofsufficient magnitude and duration to produce an upward movement o1' theprojection 44 in consequences of the heating of the thermally responsiveelement l5, then the trip latch support 4I will be turnedcounterclockwise against the bias of the relatively light spring 43 torelease the latch 40 from the catch 33, whereupon the pressure existingbetween the shoulder 35 on the trip lever 25 and the web of the catch 33in consequence oi the tension in the springs 41 will cause the catch 33to rotate in a clockwise direction about its pivots 34 and thus causethe trip lever to ride up over the top of the catch 33. In so doing, thesupport or pin 30 at one end of the toggle 23-23 is free to move to theright whereby the toggle is caused to collapse under the action of thesprings 41 and thus to cause the circuit opening movement of the movablecontact 3. During this circuit opening movement, the operating element45 is caused to move clockwise about its pivots 45 and the parts arepositioned as shown in Fig. 5. In this tripped open position, thecircuit controlling member 3 comes to rest against the compound spaceron the pin 23, the arm 32 of the toggle link 23 comes to rest againstthe latching lever 25, and the insulated pin 43 on the operating element45 comes to rest against the outer upper edge 5I of the latching lever25. 'I'he shoulder 35 on the latching lever 25 is to the right of theweb portion of the catch 33, and the trip latch 43 is in back of the webportion of the catch 33. The operating handle 52 is in its intermediateposition.

When it is desired to close the circuit breaker, the operating handle 52must first be moved downwardly to the reset position shown in Fig. 4.During this movement, the stress in the overeenter springs 41 isincreased and the insulated pin 43 rides downwardly along the upperouter edge 5| of the latching lever 25 to turn this lever clockwise andmove the shouldered portion 35 back of the web portion of the catch 33,as shown in Fig. 4. Under these conditions, the force of the springs 41exerted on the pin 3l may be resolved into two components, one in linewith the link 25 and the other in line with the link 23. 'I'he force inline with the link 23 merely tends to hold the circuit controllingmember 3 against the insulated pin 23, and the force in line with thelink 23 tends to turn the latching lever 25 counterclockwise. 'I'heforce of the springs 41 exerted on the pins 43 tends to turn theoperating element 45 clockwise labout its pivot 43. This clockwiseeffect of the operating element is transmitted to the latching lever 25by virtue of the insulated pin 43 which gears against the upper outeredge 5I of the latching lever. This turning eiiect of the operatingelement on the latching lever accordingly tends to move the latchinglever clockwise in opposition to the counterclockwise torque exertedthrough the line 28. In accordance with my invention, these two torqueson the latching lever 25 are so proportioned by the arrangement of theparts that the counterclockwise torque is slightly predominant wherebyto maintain the latching lever in engagement with the catch which ismoved up into engagement with the latching lever by the torsion spring31. Following the upward or counterclockwise movement of the catch 33,the support 4I of the trip latch is m`oved clockwise under the bias ofthe spring 43 into engagement with the projection 44 on the thermallyresponsive element. There is now a small clearance between the web ofthe catch 33 and the top of the latch lever 40, as shown in Fig. 4. Whenit is desired to close the circuit breaker, the operating handle 52 ismoved upward from the reset position shown in Fig. 4 to the closedposition shown in Fig. l. During the initial part of this upwardmovement, the operating element 45 is turned counterclockwise therebymoving the insulated pin 43 away from the outer edge 5I of the latchinglever i5 25. When this occurs, the clockwise torque exertthe trip latchsupport 4I.

acusar It will be noted that the torce exerted on the trip latch supportIl by virtue of the tendency of the catch 33 to move clockwise in thereleasing direction is exerted substantially in line with or onlyslightly to the right of the pivot pin 42 oi' This adds to thesensitivity of the tripping action consequent upon the double latcharrangement, and this is further enhanced by the application of theforce of the engagement with said lever, a trip device having a latchfor holding said catch in engagement with said lever to maintain thecircuit controlling member in the closed circuit position, biasing meanstending to move said latch into holding .engagement with said catch, atoggle interconnecting said lever and said member and arranged to beoverset to hold the member in the closed circuit position, a pivotallymounted operating element movable in one direction to eiIect engagementof said lever and said catch, and a resilient overcenter connectionbetween said element and said toggle -for biasing said member to theopen thermally responsive element at a much greater distance from thepivot 42. During the upward movement of the operating handle 52, theoperating element 45 is moved clockwise to straighten the toggle 2&-29and move it overcenter into the holding position, shown in Figs. 1, 2and 3, where it is maintained by the latching lever 25 while in thelatching position.

While I have shown and described my invention in considerable detail, Ido not desire to be limited to the exact arrangements shown, but seek tocover in the appended claims all those modincations that fall Within thetrue spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. An electric switch comprising a movable circuit controlling member,means for maintaining said member in the closed circuit positionincluding a pivotally mounted latching lever, a wedgy catch for saidlever biased into self-releasing engagement therewith, a trip devicehaving a latch for holding said catch in engagement with said lever tomaintain the circuit controlling member in the closed circuit position,and an overcenter spring operating mechanism for biasing said member tothe open circuit position and having an operating element movable in onedirection to eiect engagement of said lever and said catch and in theopposite direction to eiect engagement of said latch and said catch andto move said member to the closed circuit position.

2. An electric switch comprising a pivotally mounted circuit controllingmember, means` for maintaining said member in the closed circuitposition including a pivotally mounted latching lever, a wedgy catch forsaid lever biased into self-releasing engagement therewith, a tripdevice having a latch for holding said catch in engagement with saidlever to maintain the circuit controlling member in the closed circuitposition, a toggle interconnecting said lever and said member andarranged to be overset to hold the member in the closed circuitposition, a pivotally mounted operating element movable in one directionto effect engagement of said lever and said catch, and a resilientovercenter connection between said element and said toggle for biasingsaid member to the open circuit position and operative on reversemovement of the element to eiIect engagement of said latch and saidcatch and to move said toggle overcenter and thereby operate said memberto the closed circuit position.

3. An electric switch comprising a pivotally mounted circuit controllingmember, means for maintaining said member in the closed circuit positionincluding a pivotally mounted latching lever, a wedgy catch for saidlever, biasing means tending to move said catch into self-releasingcircuit position and operative on reverse movement of the element toeffect engagement of said latch and said catch and to move said toggleovercenter and thereby operate said member to the closed circuitposition.

4. An electric switch comprising a pivotally mounted circuit controllingmember, means for maintaining said member in the closed circuit positioncomprising a pivotally mounted latching lever, a pivotally mounted catchfor said lever, biasing means tending to move said catch intoself-releasing engagement with said lever, a pivotally mounted triplatch for holding said catch in engagement with said trip lever tomaintain said member in the closed circuit position, biasing meanstending to move said latch into holding engagement with said catch,electroresponsive means for moving said latch in the releasingdirection, and an overcenter spring operating mechanism for biasing saidmember to the open circuit position and having an operating elementmovable in one direction upon the release of said latch into engagementwith said lever during .the circuit opening movement of the member andmovable further in said direction to eilect reengagement of said leverand said catch,vsaid operating member being movable in the oppositedirection to eiect reengagement of said latch and said catch and to movesaid member to the closed circuit position.

5. An electric switch comprising a movable circuit controlling member,means for maintaining said member in the closed circuit positionincluding a pivotally mounted latching lever, a wedgy catch for saidlever pivotally supported for movement about an axis substantiallyparallel to the pivotal axis of said lever, biasing means tending tomove said catch into self-releasing engagement with said lever, a tripdevice having a latch for holding said catch in self-releasingengagement with said lever to maintain said member in the closed circuitposition and pivoted for movement about an axis substantially parallelto the pivotal axis of said catch, biasing means tending to move saidlatch into holding engagement with said catch, and an overcenter springoperating mechanism for biasing said member to the open circuit positionupon operation of said tripping device and having an operating elementmovable automatically thereby in one direction and manually movablefurther in said direction to eiect reengagement of said lever and saidcatch. said operating member being movable in the opposite direction toeiect reengagement of said latch and said catch and to move said memberto the closed circuit position.

6. An electric switch comprising a movable circuit controlling member,means for maintaining said member in the closed circuit positionincluding a plvotally mounted latching lever, a wedgy catch for saidlever pivotally supported for movement about an ams substantiallyparallel to the pivotal axis oi said lever, a spring connected betweensaid lever and catch tending to move said catch into self-releasingengagement with said lever, a trip device having a. latch forself-releasing said catch in holding engagement with said lever tomaintain said member in the closed circuit position and pivoted formovement about an axis substantially parallel to the pivotal axis ofsaid catch, a spring connected between said latch and catch tending tomove said latch into holding engagement with said catch, a movable stopfor limiting the movement of said latch in the holding direction havingelectroresponsive means for actuating said stop to move said latch inthe releasing direction, and an overcenter spring operating mechanismfor biasing said member to the open circuit position having an operatingelement movable automatically in 'one direction upon release of saidlatch into engagement with said lever during the circuit openingmovement ol said member and manually movable further in said directionto eifect reengagement oi said lever and said catch, said operatingmember being manually movable in the opposite direction to eiiectreengagement of said latch and said catch and to move said member to theclosed circuit position.

"l. An electric switch comprising a pivotally mounted circuitcontrolling member, means for maintaining said member in the closedcircuit position comprising a pivotally mounted latching lever, apivotally mounted catch for said lever having self-releasing movement inone direction, biasing means tending to move said catch intoself-releasing engagement with said lever, a pivl0 otally mounted triplatch for holding said catch in engagement with said trip lever tomaintain said member in the closed circuit position, biasing meanstending to move said latch into holding engagement with said catch,electroresponsive means for moving said latch in the releasingdirection, the respective pivotal axis of said lever and latch beingsubstantially in line with the points of engagement of the latch by thecatch and the lever by the latch to provide a highly sensitive releaseof the lever upon rotary movement oi' the trip latch out of said line bythe electroresponsive means when energized in response to apredetermined abnormal circuit condition, and an overcenter springoperating mechanism for biasing said member to the open circuit positionand having an operating element movable in one direction upon saidrelease of said lever into engagement with said lever during the circuitopening movement of the member and manually movable further in saiddirection to effect reengagement of said lever and said catch, saidoperating member being manually movable in the opposite direction toeii'ect reengagement of said latch and said catch and to move saidmember v to the closed circuit position.

JOHN A. FAVRE. REFERENCES CITED UNITED STATES PATENTS Name Date RunkeSept. 5, 1944 Number

